1. Field of the Invention
The present invention relates to a mathematical expression input apparatus, a mathematical expression modification method, and a storage medium storing a program, capable of enabling various mathematical expressions to be input.
2. Description of the Related Art
Voice recognition techniques have developed remarkably and have been put to practical use in various fields. For example, when a keyword is input by voice to a mobile terminal that is connectible to the Internet, voice recognition is carried out and a server on the Internet to which the terminal is connected searches for the keyword to provide information.
Thus, it is expected that when a mathematical expression is input to an electronic device having an alpha calculator or a calculation function, the inputting is carried out based on the voice recognition instead of key operations.
When a mathematical expression is input by voice, a manner of delimitation presents a problem.
For example, whether to convert a voice input “sine thirty plus five” into mathematical expression sin (30)+5 or mathematical expression sin (30+5) cannot be determined simply by voice.
For conventional mathematical expression voice input apparatuses, a technique has been proposed which takes a difference in the length of a silent interval in a voice input into account. For example, if the voice input sounds like “sine thirty-plus-five”, the input is converted into the mathematical expression sin (30+5). If the voice input contains a long pause after “thirty” as in “sine thirty . . . plus five”, the input is converted into sin (30)+5 (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2003-255978).
The conventional mathematical expression voice input apparatus recognizes a difference in the length of a pause in the voice input to determine the structure of the mathematical expression. However, the resultant input is far from natural reading of a mathematical expression to be input.